First Born: Watch that Blood Pressure

Heart specialists may need to ask patients their birth order

Researchers in New Zealand released results earlier this year showing that first-born children have increased risk factors for cardiovascular disease and diabetes. A study of 85 healthy children ages 4 to 11 revealed that the first borns in the group had increased daytime blood pressure and reduced sensitivity to insulin compared to children who came later.

The study looked at children before the age of puberty so that adult lifestyle factors would not affect the outcome, and all birth factors were within the same range so as not to skew results (such as birth weight and parents’ body composition). The increase in blood pressure for first borns was a few units higher and the reduction in insulin sensitivity was around 20 percent.

“The results of the current study are important,” he says, “however, more studies need to be done to determine how this translates into managing heart patients. While all young people at risk for heart disease should live a healthy lifestyle and manage risk factors, this may be more important for first born children.”

Study author, Wayne S. Cutfield, MBChB, DCH, of the Liggins Institute, speculated that the environment in utero for the first-born pregnancy could be playing a role. While the study was small, he noted that its components were “very intricately characterized.” Previous studies have also described a higher blood pressure for first-borns but were less precise. The research found blood lipids unaffected by birth order.

There has been a good deal of media attention on the results of this research, particularly in China, where there is a one-child policy. But experts agree that larger studies will need to be conducted to discover if this is a consistent finding.

Conclusion

Dr. Cutfield concluded: “Our results don’t mean that first-born children will automatically progress to diabetes or hypertension, because a multitude of factors contribute, but they may need to pay greater attention to a healthy lifestyle.”

Study results were published in the Journal of Clinical Endocrinology & Metabolism.